The present invention is directed to a damping apparatus for use with bicycle forks, the apparatus of the type that provides fluid damping.
Conventional bicycle forks connect a front wheel of a bicycle to a bicycle frame so that the rider can rotate the front wheel and steer the bicycle. The bicycle fork typically includes a fork steerer tube that is easily rotated by handlebars. The steerer tube is coupled to a fork crown that extends across the top of the bicycle wheel. Two blades extend from opposing ends of the fork crown on opposite sides of the wheel to securely attach the crown to opposite sides of an axle of the front bicycle wheel.
Bicycle forks are not only used to steer bicycles, but they are also used to absorb various loads that are experienced by a front wheel of the bicycles. See, for example U.S. Pat. No. 5,445,401 to Bradbury. These conventional bicycle forks are known to include inner and outer telescoping members that are compressible toward one another and expandable away from one another to absorb shock.
In rough terrain, however, these telescoping bicycle forks often rebound too rapidly after hitting a large bump. Some bicycle riders have also found that traditional telescoping bicycle forks compress too rapidly upon hitting small bumps. Therefore, manufacturers of bicycle forks have developed damping apparatuses that have damping mechanisms for controlling the relative movement between the telescoping members. See, for example U.S. Pat. No. 5,445,401. Although bicycle riders have embraced damping bicycle forks, as riders maneuver their bicycles over rougher terrain for longer lengths of time heat build-up within the damping fluid can cause some traditional forks to xe2x80x9cseizexe2x80x9d due to pressure buildup in a closed system. This undesirable result has led some riders to use a damping apparatus that allows the damping oil to freely circulate between the two telescoping legs. Such an apparatus, however adds unnecessary weight to the bicycle and is difficult to dissemble. It would be beneficial to provide a damping apparatus that is incorporated into a bicycle fork that provides individual compression damping and rebound damping.
Accordingly, one illustrative embodiment provides a bicycle fork having a damping apparatus. The damping apparatus comprises a cylinder, a shaft, damping fluid, and a piston. The cylinder defines a chamber within which the shaft is disposed. The damping fluid is located in the chamber. The piston is also disposed in the chamber and is coupled with the shaft. The piston is movable relative to the shaft between first and second positions. The piston also has a fluid flow aperture disposed there through and a valve structure associated with the piston. The valve structure is movable between engaged and disengaged positions. The fluid flow aperture is occluded when the valve structure is engaged and is exposed when the valve structure is disengaged. The piston is movable from the first position to the second position as a result of an external force being applied to the fluid which acts on the piston. When the piston is in the second position, the fluid is caused to move through the fluid flow aperture and move the valve structure to the disengaged position. Further illustrative embodiments comprise a bias member associated with the piston, the shaft including first and second apertures in communication with each other with each aperture positioned on opposed sides of the piston. The first aperture is occluded when the piston is in the first positioned and is exposed when the piston is in the second position.
Another illustrative embodiment of the bicycle fork provides a damping apparatus comprising a cylinder a damping fluid and a floating piston. The cylinder defines a chamber. The damping fluid is located in the chamber. The floating piston disposed in the chamber and is positioned adjacent the fluid.
Additional features and advantages of the apparatus will become apparent to those skilled in the art upon consideration of the following detailed descriptions exemplifying the best mode of carrying out the apparatus as presently perceived.